内置式永磁同步电机的效率最优直接转矩控制

为提高内置式永磁同步电机驱动系统的运行效率,提出了一种内置式永磁同步电机的效率最优直接转矩控制方法。在建立计及定子铁心损耗的内置式永磁同步电机模型的基础上,分析了电机损耗与转矩、转速和定子磁链的关系,导出了不同运行工况条件下效率最优定子磁链幅值的计算式。通过动态调节定子磁链给定值,实现了内置式永磁同步电机直接转矩控制系统的效率最优控制。实验结果表明,给出的优化控制策略在保持直接转矩控制快速动态响应特性的同时,可有效提高电机的运行效率。     

Rotor position estimation method of IPMSM using HF signal injection and sliding‐mode controller

This paper presents a simplified algorithm for the estimation of rotor position. A high‐frequency (HF) sinusoidal voltage is injected into the stator of a motor. An interior permanent magnet synchronous motor (IPMSM) has spatial saliency because the d‐ and q‐axis inductances are different from each other. The injected HF voltage is influenced by this saliency. Therefore, the rotor position is included in the stator current of the motor. The proposed method uses different synchronous reference frame transformations (SFTs) to extract the rotor position error between the estimated value and actual value. Also, a sliding‐mode controller is used for robustness against parameter variation and external disturbance. The experimental results confirm the effectiveness of the proposed method by showing waveforms of the rotor speed and position with load conditions. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Loss Analysis of Permanent-Magnet Motors With Concentrated Windings—Variation of Magnet Eddy-Current Loss Due to Stator and Rotor Shapes

In this paper, we investigate losses, including magnet eddy-current loss of permanent-magnet synchronous motors with concentrated windings. A 3-D finite-element method that considers carrier harmonics of pulsewidth modulation inverters is utilized to calculate the losses in each part of the motor separately. A simple linear magnetic circuit model is also introduced in order to understand the mechanism of eddy-current loss generation in the magnet. First, the measured and calculated results are compared to verify the validity of the analysis. Next, the variation of the losses due to the stator and rotor shapes is investigated, for instance, concentrated and distributed stator windings and interior and surface-mounted permanent magnets. It is clarified that the eddy-current loss of the permanent magnet in the concentrated winding motor is much larger than that in the distributed winding motor. The difference of the loss generation mechanism due to the rotor shape is also clarified.     

Reduction of Vibration in Concentrated Winding Permanent Magnet Synchronous Motor by Means of Skew Effects of Rotor

Global warming and the problem of successfully incorporating environmental safeguards are promoting the need for a more power‐efficient motor. Therefore, as a driving source, permanent magnet synchronous motors (PMSMs) with concentrated winding are widely used in a variety of fields. However, a PMSM with a concentrated winding generates more vibration than one with a distributed winding because of the radial electromagnetic force. This paper describes the effect of a new skewed rotor on the characteristics of a concentrated winding PMSM. We investigated this effect by three‐dimensional finite element method (3D FEM) analysis and measurement. We also demonstrate that the proposed rotor is effective in reducing the radial electromagnetic force without decreasing motor efficiency. © 2014 Wiley Periodicals, Inc. Electr Eng Jpn, 187(2): 33–43, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22400     

Analysis of the steady-state components in a balanced single-phase synchronous reluctance motor with a running capacitor

Torque pulsations arising from rotor saliency and stator winding imbalance degrade the performance of single-phase reluctance motors. This paper examines different components of torque produced by such a motor and studies their individual dependencies on machine operational indices in the steady state. The torque expressions are derived in component parts by d–q harmonic balance as functions of load angle and auxiliary winding capacitor value from which performance is assessed. By adjusting the capacitor value using established conditions for balance, improved drive performance as a 2-phase motor is realized. Simple test results were used to assess the validity of the harmonic balance model and a good agreement is observed. Torque pulsations due to stator winding imbalance were reduced while that due to rotor saliency remained unaffected as expected. The improvement in efficiency under balanced conditions, permit the motor to support a higher load torque than rated.     

一种内置式永磁同步电机直接转矩控制系统的效率优化方法

提出了一种适用于内置式永磁同步电机(IPMSM)直接转矩控制驱动系统的效率优化方法。基于考虑铁心损耗的IPMSM模型,对电机损耗与运行转速、电磁转矩以及定子磁链三者之间的关系进行了研究分析。根据典型的IPMSM直接转矩控制不使用零电压矢量的特点,对电机功率损耗计算式进行了简化,推导得出在一定运行工况条件下IPMSM的效率最优定子磁链幅值。仿真结果验证了该方法不仅可以保持直接转矩控制动态响应的快速性,而且有效地提高了电机在稳态运行时的效率。     

Optimal current control methods of a non‐salient pole hybrid field‐synchronous motor for energy‐efficient and wide speed‐range operation

This paper proposes new practical optimal current control methods for a newly emerging class of non‐salient pole synchronous motors with hybrid rotor fields by both permanent magnet and winding. In practical situations with limited voltage, the extensively used permanent magnet synchronous motor hardly achieves an ideal performance that allows simultaneously both low‐speed high‐torque and wide speed‐range operations, due to its constant magnet field. Hybrid field synchronous motors (HFSM) have recently emerged to achieve ideal performance as practical motors with controllable hybrid rotor field. For HFSM, the same torque can be produced by a variety of currents due to nonlinearity between torque and currents. Consequently, appropriate determination of a set of stator and rotor current commands plays a key role in achieving possible energy‐efficient and wide speed‐range operation. Proposed methods determine the current commands corresponding to a given torque command such that total winding copper loss due to stator and rotor currents can be minimized if the exact solution exists; the best approximate torque can be produced if no exact solution exists. The determined current commands are optimal in the sense of energy efficiency or degree of approximation in wide speed‐range operation under voltage limit. New real‐time recursive algorithms searching the optimal current solution are also given. The proposed methods are analytical but practical, and their usefulness is verified through experiments. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(1): 70–83, 2006; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.20156     

定子齿顶偏心对压缩机用IPMSM振动噪音的影响

采用分数槽集中绕组的内置式永磁同步电机(IPMSM)变频驱动的压缩机,其振动噪声有增长的趋势且存在许多新的特征。为此,本文基于定子绕组电动势和电流的谐波,建立径向和切向电磁力的等效表达式,用以分析该种电机振动噪音的产生机理;提出用定子齿顶偏心结构来抑制绕组电动势谐波,从而抑制振动噪声;用有限元法计算了该结构多个方案的电磁振动噪声,并进行了样机制作和实验,表明定子齿顶偏心可有效降低分数槽集中绕组IPMSM变频驱动压缩机某些关键频段的噪音。     

基于高频信号耦合注入的内置式永磁同步电机

内置式永磁同步电机(IPMSM)受转子凸极性的影响,绕组电感随转子磁极位置呈周期变化。考虑到上述特征,提出一种基于高频信号注入的IPMSM转子初始位置检测方法。将高频信号依次注入定子两相绕组,并提取定子绕组高频信号线电压,运算处理后获得没有考虑转子磁极极性的初始位置角。随后注入脉冲电压矢量进行转子极性判断,从而获得准确的初始位置角。理论分析和试验结果表明,该方法对电阻参数依赖较小,不受逆变器非线性和电流传感器检测精度的影响,能够准确检测转子初始位置角,满足IPMSM平稳起动的要求。     

Modelling and simulation of a double‐star induction machine vector control using copper‐losses minimization and parameters estimation

This paper shows that it is possible to extend the principle of field‐oriented control (FOC) approach to a double‐star induction motor (DSIM). In the first stage, a robust variable structure current controller based on space phasor voltages PWM scheme is established. In this current controller design, only the stator currents and rotor speed sensors are used. In the second stage, the FOC method developed for DSIM is motivated by the minimization of the copper losses. The developed approach uses a loss model controller (LMC) and an adaptive rotor flux observer to compute the adequate rotor flux value minimizing the copper losses. The control variables are the stator currents or the machine input power. Compared to the constant rotor flux approach, it is proved that higher performances are achieved. However, the sensitivity of the FOC to parameter error of the machine still remains a problem. To guarantee the performance of the vector control, the stator and rotor resistances are adapted on‐line, based on the Lyapunov theory. An appropriate choice of the reference model allows building a Lyapunov function by means of which the updating law can be found. The simulation results show the satisfactory behaviour of the proposed identification algorithm. Copyright © 2002 John Wiley & Sons, Ltd.     

Sensorless drive of surface-mounted permanent-magnet motor by high-frequency signal injection based on magnetic saliency

This paper presents a new sensorless control scheme of a surface-mounted permanent-magnet (SMPM) motor using high-frequency voltage signal injection method based on the high-frequency impedance difference. In the SMPM motor, due to the flux of the permanent magnet, the stator core around the q-axis winding is saturated. This makes the magnetic saliency in the motor. This magnetic saliency has the information about the rotor position. The high-frequency voltage signal is injected into the motor in order to detect the magnetic saliency and estimate the rotor position. In this paper, the relationship between the high-frequency voltages and high-frequency currents is developed using the voltage equations at the high frequency, and the high-frequency impedance characteristics are analyzed experimentally under various conditions. The proposed sensorless control scheme makes it possible to drive the SMPM motor in the low-speed region including zero speed, even under heavy load conditions. The experimental results verify the performance of the proposed sensorless algorithm.     

High-speed synchronous reluctance machine with minimized rotorlosses

This paper presents a refined design of a high-speed synchronous reluctance machine with minimized eddy-current losses in the rotor. Design criteria are the ability of the rotor to withstand high speeds, ability to operate in vacuum, negligible zero-torque spinning losses, high reliability, high efficiency, and low manufacturing cost. The rotor of the synchronous reluctance machine consists of bonded sections of ferromagnetic and nonmagnetic steels. Finite-element code, incorporating rotor rotation, has been developed in MATLAB that calculates steady-state eddy currents (and losses) in the rotor. A stator iron and stator winding have been designed to minimize rotor losses, and two such prototype machines have been fabricated. Experimental results show an efficiency of 91% at a 10 kW 10000 r/min operating point, and rotor losses less than 0.5% of input power     

Proposal and Feasibility Study of the Integrated Diode Synchronous Motor

This paper presents a new type of magnet‐free motor that has concentrated stator windings and rotor coils with a pair of diodes. The most important feature of this motor is that currents in the rotor coils can be generated by utilizing the changes in the spatial second harmonic of the magnetic fields due to the concentrated stator windings, which normally increase motor losses. A prototype of the motor was designed and fabricated, and its basic performance was evaluated. First, using simplified analytic models, we explain the mechanism of inducing currents in the rotor coils by the changes in the spatial second harmonic of the magnetic fields. Second, we compare the torque performance of the proposed motor and that of other types of motors including a magnet motor through finite‐element analyses. The analyzed data show that the proposed motor can possess greater torque/volume ratio than that of the other motors. Finally, using the measured data, we validate the mechanism of inducing currents in the rotor coils, and examine the torque and power characteristics of the motor.     

无刷双馈电机谐波铜耗与铁耗的分析与计算

针对无刷双馈电机谐波含量高、谐波损耗大的问题,提出考虑谐波磁场、谐波电流、集肤效应和旋转磁化影响的BDFM损耗计算模型.基于二维场路耦合时步有限元模型和谐波分析方法,分别建立两种转子铜耗计算模型和三种定转子铁耗计算模型,分析不同计算模型对转子铜耗和定转子铁耗的影响,得到定转子谐波铜耗和铁耗的变化规律.结果表明,转子铜耗模型2以及定转子铁耗模型3更精确;随着控制绕组电压的增加,定转子铜耗先减小后增加,定转子铁耗持续增加;随着负载转矩的增加,定转子铜耗和铁耗均随之增加.通过与一台相似异步电机铜耗和铁耗的电磁设计数据和实验数据的比较,验证了模型与计算结果的正确性.     

A new energy recovery scheme for doubly fed, adjustable-speedinduction motor drives

A new speed control scheme for a wound-rotor induction motor utilizing feedback of the slip power to the stator winding by means of taps is described. It is shown that with this feedback system, the motor can be operated over a very wide range even to slips reaching 0.75. The new concept eliminates the need for a transformer. The selection of feedback point on the stator winding, the equivalent circuit, and the main parameters of this system are discussed. Test results on a wound rotor induction motor are shown, and these indicate that this system also has good performance in addition to its potential for lower cost     

A brushless three-phase synchronous motor using the armature winding as both load and DC excitation winding

This paper presents a new brushless three-phase synchronous motor which has no exciter. The technique applied to the motor provides an effective way for conventional brushless synchronous motors to simplify the system configuration. The stator of the motor is equipped with a double-star connected armature winding which has two neutral points. The rotor is a cylindrical one, which is equipped with a two-phase field winding. The field winding is connected with shaft-mounted rectifiers. A dc voltage is applied to the two neutral points of the armature winding to obtain the rotor excitation when the motor is operated at synchronous speed. At that time. the armature winding acts as a stator dc exciting winding while also acting as a load winding. In this paper the principle and characteristics of the motor are described. and the experimental results are shown. It is confirmed that with a 2-kW experimental machine, the proposed motor has good performance. For example, by adjusting the stator dc current, this motor power factor can easily be controlled within a wide range.     

A comparison of the wound rotor and nested‐loop rotor brushless doubly fed generator

Both the wound rotor and the nested‐loop rotor can realize the coupling with the power winding (PW) and control winding. And the two types of rotors in a brushless doubly fed generator (BDFG) can realize variable‐speed, constant‐frequency generation. In this paper, the two types BDFG are compared through finite element analysis and experiments. From the finite element simulation results, it can be seen that the air gap flux density harmonic contents, PW line voltage harmonic contents, and the core loss of the nested‐loop rotor BDFG are higher than those of the wound‐rotor BDFG. In the experiments, the efficiency of the wound rotor BDFG is slightly lower than that of the nested‐loop rotor BDFG when the rotor speed is below the natural synchronous speed and is much higher than that of the nested‐loop rotor BDFG when the rotor speed is above the natural synchronous speed. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

分数槽集中绕组定子磁动势的分解

介绍了单元电机的基本概念。以12槽双层的分数槽集中绕组为例,给出绕线原则,并在不确定单元电机极对数的情况下,用交流电机绕组理论、函数的傅里叶级数展开两种方法,从一个线圈、一组线圈、一相绕组到三相绕组详细推导了分数槽集中绕组各次谐波的绕组因数和磁动势,得出了分数槽集中绕组的一般特点和普遍规律。最后指出转子极对数接近但不等于定子槽数的一半是采用分数槽集中绕组的永磁电机的最佳选择。     

High‐Efficiency Motors Using Soft Magnetic Cores

We have developed a small and highly efficient axial gap motor whose stator core consists of a soft magnetic core. First, the loss sensitivities to various motor design parameters were evaluated by magnetic field analysis. Low sensitivity to the pole number and core dimensions ( ? 2.2 dB) was found for the total loss, which is the sum of the copper loss and the iron losses in the stator core and the rotor yoke. From this we concluded that to improve the motor efficiency, it is essential to reduce the iron loss in the rotor yoke and to minimize the other losses. With this in mind, a prototype axial gap motor was manufactured and tested. The motor has four poles and six slots. The motor is 123 mm in diameter and the axial length is 47 mm. The rotor has parallel magnetized magnets and a rotor yoke with magnetic steel sheets. The maximum measured rotor efficiency is 93%. This value roughly agrees with the maximum calculated efficiency of 95%.     

基于矢量控制的定子笼型十二相感应电机极对数切换策略

针对传统感应电机(IM)恒功率调速区间有限,额定点外效率降低以及受使用场景约束的问题,为了拓宽调速和高效率工作区间以及适应多种环境运行需求,采用定子鼠笼型十二相IM替代传统分布式绕组三相IM。经过转子磁场定向矢量控制解耦出不同平面的谐波电流从而驱动电机旋转,通过控制函数对所有平面的谐波电流进行调控,能方便快捷地实现电机的极对数切换。对所提出的控制函数调控矢量解耦平面实现极对数切换的方法进行仿真验证,仿真结果表明所提极对数切换技术能够实现十二相IM在不同转速下的极对数切换,拓宽了转速调节区间,满足了不同工况工作时的高效率运转。